At 20,320 feet, Mt. McKinley towers 3.5 miles above its river plains in the heart of Alaska's Denali National Park, a 6-million-square-acre area roughly the size of Massachusetts. The mountain's Native American name, Denali, means "the great one."

The Mountain
Once a frigid outpost whose remoteness and physical hostility left it known to only a handful, Denali now stands at the heart of the same worldwide mountaineering boom that sent flocks of untested mountaineers to the slopes of Mt. Everest in 1996. This season more climbers than ever before are expected to be on Denali. Typically, of all those who try to make it to the summit, only 50% succeed.

While the brief climbing season is only three months, the National Park Service is kept busy running a medical and rescue operation unparalleled anywhere else in the United States. One in 200 climbers who attempt to climb the mountain dies trying, but many more lives are saved by the efforts of the Park Service rangers and volunteers. Unlike Everest, Denali has a staff of trained experts who patrol the mountain to educate and to take care of mountaineers faced with the extremes of arctic mountaineering. This effort, the rescues and medical care given on the mountain, and the research that has sprung from Denali's unique environment are at the heart of our story: exploring the interaction between humans, mountains, and weather.

At 63 degrees north, Denali, in addition to being the highest peak in the northern arctic latitudes, has the highest base-to-summit elevation of any mountain on Earth, rising 18,000 feet from its base. Everest, by contrast, is only a 12,000-foot-climb from the glaciers at its base. Around Denali's lower circumference, it is one of the world's most massive peaks. The rule of thumb among meteorologists is that the larger a mountain's mass, and the higher its base-to-summit elevation, the greater its impact on atmospheric circulation.

Early morning light reflects off Denali.

Denali is a spectacular illustration of this point. With its 18,000-foot rise and large circumference (60 miles around at the base), it is, meteorologists like to say, "so big it makes its own weather." Because of Denali's proximity to the Arctic Circle, the temperature at the summit routinely drops to 40 below zero Fahrenheit. To make matters worse, the low pressure zone that typically sits over the Arctic acts as a trough, sucking in winds that often whistle up Denali's slopes at 80 miles per hour. Coming from the west and south, the winds have ample opportunity to pick up moisture from the Bering Sea and the Gulf of Alaska. As a result, the mountain is frequently blasted by storms that are colder, wetter, windier and longer-lasting than those that pound the Himalayas.
Denali ranks as one of the world's coldest mountains. Adding to the extreme weather conditions, the lower barometric pressure at Denali's northern latitude means that the air up on the mountain - which is always less oxygen-rich the higher above sea level you go - is thinner still. A climber on the summit will feel like she is at 22,000 feet, not 20,320, at risk for all the ills that come with oxygen deprivation.
The Study
Each year, approximately 1,200 climbers attempt the popular West Buttress route. Because of Denali's popularity, its extreme northern weather conditions, and elevation, this mountain has become a laboratory for scientists studying humans in an extreme high-altitude arctic environment.

Throughout the month of June 2000, we will follow three climbers participating in a unique study on cold. Astronaut John Grunsfeld is making his first attempt to climb Denali, and Web audiences will be able to follow Grunsfeld's progress in a novel way. By swallowing a thermo-transmitter the size of a multivitamin pill, Grunsfeld will be able to transmit to us his core body temperature throughout the expedition. A small black box worn in his pocket will receive the temperature data transmitted by the pill. As Grunsfeld climbs in the heat of the day on the lower mountain or in the high winds approaching the summit, we'll learn about the fluctuations of core and ambient temperatures a climber endures in a one-month-long high mountain expedition. Grunsfeld will swallow a new pill each time the previous one passes through his system.

Pete Athans and Howard Donner train to rescue climbers from Denali.

Joining Grunsfeld will be Denali Guides, Colby Coombs (author of Denali's West Buttress) and Caitlin Palmer, who have stood on Denali's summit a combined 11 times. All three will take part in the study and will don sensors in their boots that will measure how cold their extremities, namely their toes, are on summit day. Through Grunsfeld, Coombs, and Palmer, we'll also learn Denali survival skillsand follow their daily progress toward the summit.

At the same time, we will document the real-time research and care given by doctors and rescue mountaineers at Denali's medical and rescue camp at 14,300 feet, the primary staging area where climbers typically acclimatize and prepare for the ascent to the upper regions of the mountain. In 1981, Dr. Peter Hackett, a world authority on altitude, set up the first medical lab on Denali to study altitude-related illnesses in climbers coming off the upper slopes. For the first time in 11 years, Dr. Hackett will be returning to Denali to join us up to the 14,300-foot camp. There he will check in with climber Pete Athans and physician Howard Donner as they rescue and treat climbers, (as
volunteers for the National Park Service) continuing the tradition set up by Hackett years earlier. Athans and Donner will tend to mountaineers in trouble due to "white-out" weather conditions, high winds, avalanches, falls in crevasses, frostbite, hypothermia, and most often, severe hypoxia (oxygen deprivation).

Through regular dispatches from the field, join this scientific adventure up the slopes of North America's highest peak.